Mast cells (MC) are an important component of many inflammatory responses such as those of immediate hypersensitivity. Two classes of MC are recognized in most species but he recent finding s of multiple proteases associated with the secretory ganules of MC in both moussena and man, has provide an alternate and more specific means of identifying different populations of MC. While the substrates for the various proteases have not been fully elucidated as yet, their differential expression suggest a finely coordinated system in which different proteases may invoke different responses in different tissues. Because of the greater number of invito-derived MC types developed in the mouse over the past several years, this system has proved very amenable to delineating all of the components of MC secretory granules. Currently, eight different proteases are defined and differentially expressed in various murine MC. Specific expression of murine MC proteases can be controlled by specific cytokines which demonstrates a developmental role for these molecules. Different cytokines have been implicated in the development of the different classes of MC in both mouse and man. This proposal aims to evaluate the controlling elements involved in the regulation of one of the controlling elements involved in the regulation of one of the MC proteases, mMCP-1, bu the cytokines IL-3 il-9, IL-1o and Kit Ligand. To defined the controlling elements upstream of the mCMP-1 gene, the flanking region will be ligated to a reporter gene and the construct will be transfected into a transformed rat mucosal MC line. In addition, the controlling elements will be evaluated by the techniques of DNase-I hypersensitivity and electrophoretic mobility-shift analyses. mMCP-1 has been chosen for this evaluation for several reasons. It exhibits tissue- specific expression in one mature mast cell subtype. It is the dominant protease expressed by MC in the intestinal mucosa following infection with various parasites. It is in in a transformed immature mast cell line by exposure to the appropriate cytokine which provide a in vitro system to delineate the various regulatory element. From the information provided by the proposal, it will be possible to better understand how cytokine interact with the MC in human tissue. This understanding then, will lead to better means to control MC response in various diseases such as asthma, allergy and mastocytosis.